1. Field of the Invention
The present invention relates to a substrate holding/rotating device, a substrate processing apparatus including the same, and a substrate processing method. Examples of substrates to be held or substrates to be processed include semiconductor wafers, substrate for liquid crystal display devices, substrate for plasma displays, substrates for FEDs (field emission displays), substrates for optical disks, substrates for magnetic disks, substrates for magnet-optical disks, substrates for photomasks, ceramic substrates, substrates for solar cells.
2. Description of Related Art
US2013/0152971 A1 discloses a rotating type substrate holding/rotating device that is composed of a rotary table that is rotatable around a rotational axis along a vertical direction, a rotation driving unit that rotates the rotary table around the rotational axis, and a plurality of (e.g., four) holding pins that are disposed at the rotary table and that horizontally position a substrate with a predetermined interval between the substrate and the surface of the rotary table.
The plurality of holding pins include fixed pins that are immovable with respect to the rotary table and movable pins that are movable with respect to the rotary table. The movable pin is rotatably disposed around the rotational axis that is coaxial with its central axis, and has a contact portion that is brought into contact with the peripheral end edge of the substrate. The contact portion is displaced by the rotation of the contact portion between an open position that is far apart from the rotational axis and a hold position that is close to the rotational axis. A pin driving magnet is joined to a rotational shaft of the contact portion.
Switching between the opening and the closing of the movable pin is performed by use of an elevated/lowered magnet disposed below the rotary table (magnet switching method). A magnet raising-and-lowering unit is joined to the elevated/lowered magnet. When the elevated/lowered magnet is at a predetermined lower position, the elevated/lowered magnet does not face the pin driving magnet, and therefore an external force that urges a movable pin toward its hold position does not act on this movable pin. Therefore, when the elevated/lowered magnet is at the lower position, the movable pin is held at its open position. On the other hand, when the elevated/lowered magnet is at a predetermined upper position, the movable pin is held at its hold position by means of a magnetic attractive force between the elevated/lowered magnet and the pin driving magnet.
The substrate holding/rotating device mentioned above is included in a single substrate processing type apparatus that processes substrates one at a time, and a processing liquid (a cleaning chemical liquid) is supplied from a processing liquid nozzle to the upper surface of a substrate being rotated by the substrate holding/rotating device. The processing liquid supplied to the upper surface of the substrate receives a centrifugal force resulting from the rotation of the substrate, and flows toward the peripheral edge part of the substrate. As a result, the whole area of the upper surface of the substrate and the peripheral end surface of the substrate are subjected to liquid treatment. Additionally, depending on the kind of substrate processing, there is also a case in which the peripheral edge part of the undersurface of the substrate is also intended to be subjected to liquid processing.